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DARWIN, CREATIONISM AND EVIDENCE

Here's something I have been working on. Comments please. It needs a final para. Warning - about 3.5k words!

DARWIN, CREATIONISM AND EVIDENCE

Introduction

Both the general theory of evolution and Darwin’s particular theory of evolution by natural selection are regularly challenged by people who describe themselves as “creationists”. There are several varieties of creationism. The focus here is on what is often called “young earth creationism”: the view that the entire universe is approximately six thousand (certainly less than ten) thousand years old, and that all living species were created within the first few days of creation. Henceforth, when I speak of “creationism”, it is young earth creationism I have in mind.

Why would anyone believe creationism? Typically, because they are Bible literalists. Creationists believe that Genesis provides an historically accurate account of origin of the universe and life. Their chronology is based primarily on the number and ages of the generations listed in the Old Testament.

Belief in creationism isn’t confined to a few religious cranks. Recent polls fairly consistently indicate that, currently, about one third to one half of all U.S. citizens are creationists. Nor is creationism solely the preserve of the unintelligent or ill-educated. It seems that significant numbers of college graduates are drawn to Bible literalism. A Tennessee academic who surveyed his own students a few years ago found that about a third were creationists. He complained that scientists like himself are having to fight

the battles of the Enlightenment all over again. Medieval ideas that were killed stone dead by the rise of science three to four hundred years ago are not merely twitching; they are alive and well in our schools, colleges and universities.

These medieval ideas are also taking root outside the U.S. Because of the evangelism of American Bible-literalists, creationism is on the rise around the world. Russia and Eastern Europe, in particular, are heavily targeted by Christian fundamentalists for whom states newly liberated from communism promise a new frontier in their project to spread creationist ideas around the world. In 2004, the Serbian education minister Ljiljana Colic succeeded (if only temporarily) in removing the teaching of evolution from all state schools, replacing it with the teaching of young-Earth creationism instead. Creationism is widespread in many African states, and also among those many Muslims for whom the literal truth of the Old Testament is also an article of faith.

For most creationists, the literal truth of the Old Testament is a “faith position”. They insist they would maintain their belief even if the scientific evidence seemed conclusively to falsify it.

Nevertheless, many creationists believe that their theory is scientifically respectable. It is, they suppose, supported by the available empirical evidence. Indeed, creationism has its own research centres – including the Institute for Creation Research – as well as its own conferences, publications and PhD-qualified researchers.

It is the claim that creationism is a scientifically robust theory at least as empirically well-supported as its rivals that I shall focus on here. How, exactly, do creationists convince themselves of the scientific validity of their theory?

The fossil record

Let’s begin with an illustration: creationist attempts to deal with the fossil record. Examination of the rock beneath our feet reveals strata that have been laid down, apparently over many millions of years. Fossils can be found embedded in these strata. And we find different life-forms fossilized in different levels. At the lowest levels, only very simple creatures are found. Higher up we discover more complex forms, including the dinosaurs. Higher still we find mammals. Only the most recently deposited layers reveal traces of man.

This layering of the fossil record tallies well with the theory of evolution, but seems to contradict the Biblical account on which all life-forms were produced more or less simultaneously about six thousand years ago. If the Biblical account were correct, we should presumably expect to find examples of the entire range of life-forms fairly randomly distributed throughout the strata (assuming, that is, that the few thousand years that have elapsed since creation would suffice to allow such rock strata even to form).

According to creationism, for example, man and all the other mammals walked the Earth at the same time as the dinosaurs. So shouldn’t we expect to find fossils of both man and all the other mammalian species muddled up in the same layers as dinosaur fossils? Yet we find distinct layering, with, for example, the larger mammals only ever appearing in the higher strata. Such evidence seems to count fairly decisively against creationism.

While the fossil record might seem to provide powerful evidence against creationism, creationists argue that the situation is not so simple. Indeed, they have shown some ingenuity in their attempts to explain how their theory also fits the available data.

Creationists maintain that the layering in the fossil record can be explained by reference to the Biblical Flood (the one on which Noah famously floated his ark). The rains that caused the Flood were responsible for producing huge mud deposits that then metamorphosed into the rock strata we find beneath our feet. Creationists insist that the ordering of the life-forms within these layers can also be accounted for on their theory. For example, some have suggested the reason we find dinosaurs below larger mammals is that dinosaurs are slow, cumbersome, comparatively unintelligent creatures that are likely to have been buried before the faster and more intelligent larger mammals that would have run to higher ground. Nor, as the Christian website www.christiananswers.net attempts here to explain, should we expect to find fossils of humans in the lower sedimentary layers. The layering we find in the fossil record

can be more reasonably explained by Flood geologists as due to the order of burial of the different ecological zones of organisms by the Flood waters. For example, shallow marine organisms/ecological zones would be first destroyed by the fountains of the great deep breaking open, with the erosional runoff from the land due to torrential rainfall concurrently burying them. On this basis we would probably not expect to find human remains in the early Flood strata, which would contain only shallow marine organisms. The fossil record as we understand it at the moment certainly fits with this.

We have here an example of a standard creationist manoeuvre: by adapting and developing their own core creationist theory in various ways, evidence that might seem straightforwardly to falsify their theory is shown, with varying degrees of ingenuity, to “fit” with creationism after all.

Similar moves are made to deal with other evidence. Take the light arriving here from distant stars. That light would in many cases have had to travel for much longer than six thousand years to arrive here. It seems, then, that the universe must be much older than six thousand years. One creationist response to this evidence is to develop a theory on which the speed of light is actually slowing down. Technical papers filled with equations have been published in support of such rival creationist theories.

Or take the slow movement of tectonic plates to produce mountain ranges and the slow process of erosion to shape them – surely a range such as the Himalayas – is powerful evidence that these processes have been in operation for millions of years, not just a few thousand?

In response, creationists have suggested that tectonic plates can and have moved much more rapidly than they do at present, and that erosion can also take place very quickly under conditions such as those that occurred during the flood (a claim which, they suppose, also accounts for structures such as the Grand Canyon).

Now, if your conception of good scientific practice is simply to develop theories in such a way that they become consistent with the available empirical evidence, then it might strike you that what creationists are practising here is, indeed, good science. They even have a “research program” of sorts: to refine and shape their core theory in such a way that it comes to fit the evidence.

What creationist scientists practice certainly looks to many like solid, respectable science. Indeed, many millions of American citizens, many of whom are intelligent, college-educated people, believe that creationism is good science. Have all these people been duped? Or is so-called “creation science” good science after all.

Whether or not creation science even qualifies as science (and I have my doubts) it certainly isn’t good science. In order to see why, we need to develop a slightly more sophisticated understanding of what good evidence is.

I am going to focus in turn on the two ways evidence can be applied – as evidence against, or for a theory.

Are dogs Venusian spies?: dealing with evidence against your theory

Suppose that, for some strange reason, I come to believe that dogs are spies from the planet Venus. Amazed I could believe anything so foolish, you proceed to wheel out counter-evidence. “But dogs can’t even speak!” you point out. My reply: “They can speak, but simply choose to hide this ability from us.” “But they have no method of communicating with Venus”, you add. I reply: “Ah, they communicate by means of secret radio transmitters.” “But we have searched everywhere, and can find no evidence of such transmitters.” I reply: “The transmitters are embedded in the brains.” “But we have X-rayed their heads, and can find no transmitters!” I reply: “The transmitters are made of an organic material indistinguishable from brain stuff.” “But we can detect no signals coming from dogs’ heads.” “The signals are sent via a medium that we are, as yet, unable to detect.” “But Venus is a lifeless, uninhabitable planet.” “The Venusians live in deep underground bunkers where they are protected from the harsh atmosphere.” And so on. You can see that, with a little ingenuity, I might continue to play this game forever. Yes, there is a mountain of evidence that dogs are not Venusian spies. And yet, for any piece of evidence you might care to wheel out, it is always possible for me to concoct some explanation for that evidence – an explanation on which my theory that dogs are Venusian spies is consistent with that evidence.

Yet, clearly, despite the fact that I can continue to make my theory fit the evidence in this way, my theory is patently ridiculous. Certainly, what I am practising is not good science.

The moral is that, whatever good scientific practice is, it requires rather more than that we simply busy ourselves constructing theories that are consistent with the available evidence.

Any theory, no matter how ludicrous, can be made consistent with the available evidence, given enough ingenuity.

Yet the approach of “creationist scientists” is, to a very large extent, similar. Orthodox scientists who attempt quickly to dismiss creationism by wheeling out evidence that seems straightforwardly to falsify it often find themselves tied up in knots by opponents, who, armed with an array of moves developed by the Institute for Creation Research, etc., are able to show how creationism really does fit the evidence after all.

There’s a further moral we can draw. We can now see that, in order for evidence strongly to confirm a theory, more is required than that the theory be consistent with the evidence. Creationist understanding of good science seems often to involve a muddling of this distinction between evidence being consistent with a theory and evidence supporting a theory.

A caveat

I have drawn a parallel between the strategy I adopted to defend my belief that dogs are Venusian spies, and the strategy adopted by creationists to deal with seeming counter-evidence to their theory. But we do need to add a caveat here. The caveat is that, actually, even reputable scientists do make these kind of moves on occasion.

Here’s an example. When the heliocentric model of the universe was proposed, objectors pointed out what seemed to be powerful evidence against the theory. If the Earth were travelling round the sun, then the fixed stars should appear to wobble back and forth across our cosmic field of view over the course of a year (in much the same way that, if I walk around a lamp post while looking due north, the houses across the street should move back and forth across my field of view). The absence of any such observable parallax was an embarrassment for the new theory, and it prompted the response that the stars must, therefore be at a much greater distance than had previously been thought, making the parallax effect so small as to be undetectable. This explanation, it later turned out, was correct, though there was no way that those who originally made it could establish this at the time.

We have here an example of reputable scientists explaining away seemingly contrary evidence in much the same way creationists explain away the evidence against their theory. This is by no means a rare occurrence in scientific circles. And why not? Surely it’s not always unreasonable to defend a theory by constructing such alternative explanations for apparent counter-evidence? But then why shouldn’t creationists adopt the same strategy?

Because, while this strategy can be reasonable, clearly there are limits. Certainly, the strategy may well be reasonable if, say, the theory is otherwise well confirmed, the contrary evidence is limited, and if the alternative explanations have further independently-testable consequences. But clearly, my defence of the theory that dogs are Venusian spies fails on at least two of these three counts. Not only is my theory is not strongly confirmed (see below), it faces so much contrary evidence that my strategy of seeking to explaining away that evidence becomes ridiculous. I end up having to devote almost all my intellectual energy to constructing ever-more elaborate explanations of why the evidence is, after all, consistent with my belief that dogs are Venusian spies.

Creationism shares both these failings. Not only is their core theory not strongly confirmed (as I will further explain shortly), much of the intellectual effort of “creation scientists” is inevitably focussed on their programme of coming up with explanations to show how seemingly contrary evidence is consistent with their theory after all.

What creationists practice might look a bit like science to the untrained eye. After all, it's true that they are using imagination and ingenuity to develop a theory that continues to fit the available evidence. But, because the spend so much of their energy attempting to explain away counter-evidence, their method is essentially unscientific.

Reasoning of the insane

We have seen that, in defending the theory that dogs are Venusian spies, my method may resemble the scientific method in certain respects, but differs essentially from it. Indeed, were I to continue to defend my dogs-are-Venusian-spies theory in this manner, not only would I start to infuriate my audience, I would quite properly be suspected of suffering from some sort of mental illness.

Indeed, in its most extreme form, this pattern of thinking – the strategy of explaining away counter-evidence ad nauseum - surely is characteristic of certain forms of insanity. Anyone who has spent some time in the company of someone who, perhaps because of a serious psychiatric condition, is severely deluded will recognize the frustration of trying to convince them of the error of their ways, when they can apply their often considerable ingenuity to developing ever-more elaborate explanations to deal with your evidence that, whatever they might think, dogs really aren’t Venusian spies.

Of course, creationists aren’t (usually) mentally ill, but it’s striking how their thinking often exhibits this same peculiar pattern of thought – a pattern that allows them effectively to seal themselves off inside a their own bizarre bubble of belief.

When does evidence strongly support a theory?

Let’s now look at how evidence can be used to support a theory. Evidence can support a theory to varying degrees, of course. An observation of a single white swan is some evidence that all swans are white. But not very much. Observe more white swans and no black ones, and the degree of evidential support increases somewhat.

Under what circumstances is a theory strongly confirmed by a piece of evidence? That’s to say, under what conditions does a piece of evidence, while perhaps not by itself sufficient to make it rational to believe the theory, nevertheless very significantly support it? It seems three things are required.

o First, the theory must allow us to deduce observational consequences: consequences that can be clearly and precisely stated.o Second, there should be a sense in which the prediction is surprising and unexpected.o Third, the prediction should turn out to be true.

The first two conditions explain why, for example, the kind of predictions made by end-of-pier astrologers and psychics rarely constitute strong evidence in support of the claim that the have genuine occult powers.

Note, first, that such predictions as that I will soon meet a dark and handsome stranger, or will come into a sum of money, or know someone with health problems, are obviously pretty vague – does “soon” mean this week, this month or this year? How much money is a “sum”, what counts as “dark”? Does the common cold count as “health problems”? This vagueness makes it far easier for the astrologer or psychic to insist that their predictions have come true.

But in fact, even without the very considerable wiggle room provided by such vagueness, these predictions may well come true anyway. Most people know someone with health problem, will soon meet a dark stranger, and will come into some money in the not too distant future. These predictions are unsurprising in this sense: that they are likely to be true anyway, irrespective of whether the hypothesis that the psychic or astrologer has genuine powers is true. In which case, the discovery that they are true provides very little evidence in support of that hypothesis.

Contrast the above “evidence” for genuine occult powers with, say, some of the evidence in support of the theory of evolution (whether or not it be Darwin’s version). From the hypothesis that all species have evolved over millions of years by increments from some common ancestor, we can derive, for example, this observational consequence: that the fossil record will be contiguous and progressive. The theory predicts that the fossils will line up in a very specific manner: a manner consistent with the claim that later species evolved from the earlier. It predicts we won’t find any out of order fossils (e.g. we won’t dig up cow fossils in the pre-Cambrian layers). It also predicts that we will discover fossils of extinct species that are morphologically transitional between existing species. The theory predicts a great may other things too, of course, but if we focus on the prediction about no out of order fossils, notice that it does met our three requirements for strong confirmation. The prediction of a contiguous and progressive fossil record is pretty clear and precise. It is also surprising in the sense we require for strong confirmation – if the theory were not true, then there would be no particular reason to expect the fossils to line up in such a precise manner. And yet, even after we have dug up millions of fossils, including many thousands of mammal and dinosaur fossils, there has not been even a single well-documented instance of an out of place fossil. If the theory were not true, the fact that there has not been even one such fossil would be a quite extraordinary coincidence. So the fact that the fossils do line up in this very particular way very strongly confirms the theory.

In response, a creationist might insist that the fact that the fossils do line up in this manner is not particularly unexpected on their alternative theory. Certainly, we have seen that they tell a story about the biblical flood that makes the actual arrangement of fossils consistent with their theory. But is, not just a rough banding of dinosaurs and humans into different layers, but this very particular kind of ordering throughout the layers predicted by the theory of evolution, something which, even according to creationism, is not unlikely? Surely not. Even if creationism can be made consistent with the fossil record, it certainly doesn’t give a particularly high probability to this very specific arrangement of fossils. So, as a prediction, it is, in the relevant sense, surprising. But then, as the prediction is also true, the theory of evolution is strongly confirmed.

What about creationism? Is that also strongly confirmed by, say, the fossil record? No. For creationism doesn’t make any clear, precise and surprising predictions regarding what we should expect to dig up. Creationism doesn’t really make any particular clear, precise and surprising predictions about what we should expect to dig up. Whatever we dig up, they can say – “Hey: that’s just what we expected!”

In short, to be strongly confirmed, a theory has, as it were, to really stick its neck out with regard to predictions – to take very significant risks so far as being proved wrong is concerned. The theory of evolution takes such risks with the fossil record, which is why it can be strongly confirmed by it. Creationism does not.

That the theory of evolution sticks its neck out so far as the fossil record is concerned, whereas creationism does not, is indeed, acknowledged in this quote from the creationist website www.answersingenesis.com:

If human and dinosaur bones are ever found in the same layers, it would be a fascinating find to both creationists and evolutionists. Those who hold a biblical view of history wouldn’t be surprised … Evolutionists, on the other hand, who believe the geologic layers represent millions of years of time, would have a real challenge. In the old-earth view, man isn’t supposed to be the same age as dinosaurs…. As biblical creationists, we don’t require that human and dinosaur fossils be found in the same layers. Whether they are found or not, does not affect the biblical view of history.

What these creationists fail to realize, however, is that it is precisely their lack of commitment one way or the other so far as how human and dinosaur fossils should be arranged that gives the theory of evolution a very significant advantage over their own. For, unlike their own theory, the theory of evolution can then be strongly confirmed by what is dug up.

Summary

I have been looking at the general strategy of creationists regarding evidence. We have seen that, to some extent, their strategy does resemble the scientific method. Indeed, it resembles it enough to fool many people into thinking that creationism is “good science”. However, we have also seen that, (i) unlike genuinely good scientific theories such as the theory of evolution (and also Darwin’s version of it), creation science expends far too much of its intellectual energy trying to explain away enormous amounts of counter-evidence, and (ii) it also (as I have at least illustrated, if not yet established) takes few risks with the empirical evidence, with the consequence that, unlike the theory of evolution (and Darwin’s version of it), it cannot be strongly confirmed by that evidence.

Evidence against evolution/ for creationism

I have not yet included everything that gets done under the banner of creation science. For example, creation scientists also spend much energy cataloguing what they consider to be evidence against Darwin’s theory, the theory of evolution more generally, and of course the theory that the universe is far older than just a few thousand years. Because every scientific theory, no matter how successful, has its problems to deal with, it’s not difficult for creation scientists to find and then widely publicize such via the internet, church meetings and events, and so on, in such a way as to give audiences the impression that, while creationism may have its problems, so do its rivals. So don’t both deserve to be taken seriously?

What such creationists presentations obscure, of course, is the sheer scale of the problems facing creationism compared to those facing the theory of evolution, etc. But in any case, many of the “problems” that the theory of evolution supposedly faces aren’t really problems at all.

Here’s just one example of such a pseudo-problem. Attend a public lecture by a creationist are you may be shown dramatic slides of fossils which, its claimed, disprove the theory of evolution. Take, for example, images of trees fossilized upright through rock strata (there are some famous examples at Yellowstone park, U.S.A.). Such polystrate fossils (see illustration above), say some creationists, are powerful evidence that these trees were buried quickly, as their creationist Flood theory predicts, not slowly over millions of years, as the theory of evolution demands (if the process were that slow, the creationists point out, then the tree would have long rotted away before any higher sedimentary layers were added). While such dramatic images and arguments may persuade some audiences, the truth is that polystrate fossils are no problem at all for the theory of evolution. The theory acknowledges that sedimentary layers are sometimes rapidly laid down (besides rivers, for example, or during a rapid series of volcanic eruptions). So, on the theory of evolution, polystrate fossils are to be expected. Evangelical creationists who present such images in such a misleading way are either woefully ignorant about fossils, or else are else are guilty of deliberately misleading their audiences. Such pseudo-problems abound in creationist media.

You might also want to discuss the difference between positive and negative evidence - and the fact that creationism is based on a false dilemma. If the creationists are right about evolution not being so, that does not prove that creationism is true - it only proves that evolution is not true.

Similarly, I think that the Omphalos argument is an interesting one to show how creationism doesn't survive Occam's Razor. Omphalos creationism is the same model of thought that we see with conspiracy theories.

Stephen, even though there are well-known difficulties with falsification, would you ever consider including it as a necessary but not sufficient criterion for a theory to be scientific? It's just that it's such an obvious defect in the methodology of creationist theories...

Well, I think that the *content* of creationism is falsifiable. Indeed, it is falsified.

However, the *method* creationists employ renders their theory unfalsifiable (it would render any theory unfalsifiable). And that is of course a problem. Indeed, I do point the problem out here, though I've avoided the label "falsificationism".

BTW, I don't endorse Popper's complete rejection of "ad hoc" responses to counter evidence (i.e. moves made to deal with apparent falsifications, but that introduce no further independently testable consequences) as scientists also do quite properly make such moves. The example above involving parallax is a well-known example, in fact.

Although the creationist debate seems to rage over missing fossils ordering etc. I think more emphasis should be placed on the geological side of it. It is after all one of the primary ways of dating fossils. Even if there were no fossils it would still show the earth to be older than the creationist claim. As indeed would dendrochronology, astronomy, study of glaciers and radio carbon dating of biological remains.

As to a fitting last paragraph, FWIW I think you probably already have one here, its just not currently at the end!. perhaps you should move the bit about polystrate fossils earlier on in the discussion?

I enjoyed reading your essay, but it is perhaps more sophisticated than it needs to be. Indeed, you highlight the real problem early on:

"For most creationists, the literal truth of the Old Testament is a “faith position”. They insist they would maintain their belief even if the scientific evidence seemed conclusively to falsify it."

Creationists don't simply object to evolution, they object to science in its entirety and the process of reason underlying it. The Discovery Institute has said so much. So attempts to appeal to reason in defence of science is of little use here, I think. That creationists often engage in a form of pseudo-science of their own isn't to be confused for evidence that they hold even a tiny bit of merit in science. Generally, it's either an attempt to gain prestige (usually among their own) by bashing those ignorant materialists with their own tools, or simply so that they can cry oppression when they're hypotheses are attacked.

IMHO, the only real way to combat creationism is to attack it primarily on theological grounds.

But how well confirmed was the heliocentric model at the point at which the issue of parallax was raised? It would still in great doubt. The evidence for it was problematic, for reasons including parallax. It would not be until Galileo came along that many of the outstanding problems of heliocentrism could be given answers. The evidence against heliocentrism was not insubstantial, and in this sense the second point there is violated, along with the first. As for the third, it would not be for some length of time that parallax was actually observable, due to the technical difficulties in observing such small relative position changes. So in the sense, the heliocentric model fails on the third point as well, at least at that point.

So when are ad hoc 'rescue operations' legitimate? I don't think there is any clear line in the sand for them - it just becomes increasingly obvious that the theory in question is so befuddled with problems that it needs rescue at every turn, and this is falsehood-indicative

(Incidentally, Bayesian confirmation theory can give us a good account of why we tend not to like/approve of ad hoc additions - the conjuction of any theory T and a modication M (T&M) must have a lower prior probability than T alone, by necessity)

I've had a lot of experience with ad hocking, as I like to call it. My former boss, who was painfully religious, could rationalize anything. That's the key to it, really. You just have to have enough smarts (or stupids) to think that your answers are always right, and then you can come up with a way to solve ANY seeming difficulty with your theory.

I may have mentioned this before, but I asked him once what evidence he had for god's "existing outside of time." He could not give any, but simply said it was self-evident. What I realized about it was that it's not that it's self-evident. Rather, it's that it has to be true for his theory to be true, so he was putting the proverbial cart before the horse. "This ad hoc hypothesis is true because my theory is true", not the other way around. That seems to be the prevailing mindset of most creationists.

Another common fallacy that they use is selective evidence. Consider that my former boss only read enough about evolution by scientists who he KNEW didn't agree with it to get the idea that it must be false. He didn't go any further, and in fact refused to, claiming that the likes of Stephen Jay Gould should be good enough for the likes of me to not believe in evolution.

Overall, I'm really lucky that I got to get out of that place. The people there were just too radical and dangerously religious - the kind of Xians that I would expect to be suicide bombers.

There is nothing necessarily wrong with reasoning in the way that your boss did.

Suppose the prosecution presents solid evidence in favour of the guilt of person X. They were found in possession of goods matched to those that were stolen from the premises in which X worked. The defense however points out that the prosecution has no theory to offer about *how* X obtained the goods. In short, they don't know how or when he got into the locked room in which the goods were kept - but they nonetheless accuse of X of guilt because he had opportunity, but moreover, he was found with the goods.

Does the prosecution explicitly need to offer an account by which X got into the room, and when? Not necessary - a good case can be made simply in virtue of X's guilt being the best explanation for X's having the goods.

The "cart before the horse", as you call it, can be quite reasonable in cases.

I agree with the Rev. Dr. and suspect that your elegant arguments will, Stephen, just fan the fires of creationist science. Furthermore, I shall now argue that you have put the cart before the horse (or begged the question, or something like that).

But first, recall David Lewis, that giant of modern philosophy. His Humean Supervenience is defended by pure ad-hoccery but it made him a Naturalistic giant because (i) it is addressed ad nauseum by professional philosophers and (ii) it is admissible within Naturalism because it can accommodate all scientific theories, and furthermore it has a certain metaphysical sparseness to it, which is very scientistic.

Similarly, and more scientifically, the many-minds interpretation of quantum mechanics, or physicalism about the mind; and creationism is similarly metaphysically sparse.

There is a lot of evidence for Darwinism, but there is also a lot of evidence for, say, Newtonian space, and yet that evidence is all reinterpretted nowadays. Creationists can say that Darwinists are not allowing for enough of the available evidence. (They would include non-scientific evidence, but then, so do those scientists who allow that, say, our personal knowledge of our own consciousnesses is evidence against certain physicalisms in psychology.)

And the creationists are not stuck with any of their sillier suggestions, only with Genesis and the brute evidence. If you do manage to show that one of their suggestions is silly, without just ignoring some of their assumptions, they can easily make up another, and thank you for helping to improve some of the (for them insignificant) details of their theory.

And the obvious implausibilities in Genesis (people living for hundreds of years, giants, the Ark actually floating and so forth) just imply, for young earth creationists, that the laws of physics have probably changed in the few thousand years since the Fall, probably as a result of that Fall. So all your scientific evidence against Creationism is not actually touching their version of Creationism - they already had evidence of their own that physical laws were different in the past. (Laws can be defined to be temporally invarient, but I'm just thinking of the existing laws, e.g. relativity theory; one could say instead that the physical laws are more complicated than they seem.)

Why, if there was a God, would laws of physics not change, as the more important ethical status of His creatures changed? Darwinian evolution is an extrapolation back in time from current physics and biology, but creationists have reason, in the form of revelation (which compares not too unfavourably with particle physics these superstringy days), for doubting that extrapolation. They have reason for expecting the extrapolation to be physically tidy though (since the current physics is made by an infinite God), indeed for there to be such tidiness as makes Darwinists feel that they must be right (as the Newtonians felt they were).

I can't see much point to the Creationist explanations you rightly ridicule, but they are not as mad as they seem. Physics has probably changed (if the relevant revelation has any weight, which is a different question) in the last few thousand years, but how? Well, the author of the world can change the nature of spacetime as easily as he can make any spacetime up in the first place. For creationists, the actual story involves all of us, and the people of the Bible in the sequence given therein, primarily.

You are probably assuming that modern physics is primary, but that is not a very theistic assumption. How different would past physics probably be? The most scientific thing is to postulate minimal changes, which is what the creationists do - they are theists, so they allow the physics to have changed, which you have not allowed for, and place a higher value on their religious accounts of the people of the past (much as some scientists place such a high value on certain forms of evidence that they deny, quite scientifically, that subjective experiences can challenge physicalistic approaches to mind). They are only speculating about what might explain the physical evidence from a long time ago, when they would expect (i) the physics to have been different in some obscure ways, but also (ii) that it would have supported (in its own ways) animal life much as it is today.

In short, you have not shown that they are being unscientific, only what they know (and we should know), that they have different metaphysical assumptions.

Suppose the prosecution presents solid evidence in favour of the guilt of person X. They were found in possession of goods matched to those that were stolen from the premises in which X worked. The defense however points out that the prosecution has no theory to offer about *how* X obtained the goods. In short, they don't know how or when he got into the locked room in which the goods were kept - but they nonetheless accuse of X of guilt because he had opportunity, but moreover, he was found with the goods.

In such a case, you would be able to prove that X was guilty of possession of stolen goods, but not of stealing those goods. Your argument is not valid, and neither are analogous arguments, by creationists or anybody else.

are jointly sufficient for such moves to be legit. I didn't say they were singly necessary. So I don't run into any problems with the heliceontric example you cite. Maybe I should spell this out, though....

By the way, I didn't use Popper's def of "ad hoc" moves - no independently testable consequences - and then say that explanations for counter evidence must not be ad hoc, because the parallax example, as Kosh3 points out, is ad hoc yet legit., whereas many creationist moves are not ad hoc (the prediction about slower animals unable to run to higher ground, for example gives rise to further predictions...).

The problem with creationist explanations is not the ad hoc-ness of the moves (they are not all ad hoc) - it's the overall pattern - they just spend too much time explaining away the evidence, whether or not by ad hoc means.

Since I allege that early heliocentric attempts at explanation could be said to have failed in all three areas, I think you must say (if you hold that all 3 are jointly sufficient) that early heliocentrism was unjustified in making ad hoc alterations. But I am not sure I would want to say this, and as such, I don't think the three conditions you cite are jointly a demarcation criterion between appropriate and inappropriate ad hoc changes.

Its an inspiring essay. I've been puzzling about "evidence FOR" and am on re-write five of a paper. You've inspired me to finish it!

I think your paper does come down to Popper. Your first two criteria combine to give the logical improbability of a proposition:

o First, the theory must allow us to deduce observational consequences: consequences that can be clearly and precisely stated.o Second, there should be a sense in which the prediction is surprising and unexpected.

But splitting them back out we have:1. Explanatory power of the theory2. Testability of the theory

Creationism, of course, fails on both counts but your piece reads a little top heavy on explanatory power.

On the second criterion, why is a prediction "unexpected"? I would say that it is because other knowledge fails to predict it. So throwing an apple and watching it fall fails to be evidence FOR relativity. The same thing is predicted by Aristotelianism, Newton and the Flying Spaghetti Monster. The perihelion of mercury on the other hand......

My suggestion is to drop the astrology and look to a situation were even the creationists would agree on both criteria: a police investigation and prosecution. Suppose Ken Ham were accused of crime. Either Ken Ham or Stephen Law could have done it, but finding out isn't the aim of the police, the aim of the police is to start off from the idea that Ken Ham did it. They find "evidence" and construct a theory that interprets that evidence in accordance with that paradigm (it was a Tuesday, Ken Ham was alive on the Tuesday! It was done with a knife, Ken Ham owns a knife! Ken Ham COULD have done if X, Y and Z had happened)

What even the creationists would agree is that we should look for evidence that can be deduced from "X did it" and NOT from "Y did it". The blood on Stephen Law's shirt would do. We would expect it if Stephen had done the crime, we would not if Ken had done the crime. It may not be conclusive but its evidence FOR in a way that holes in the Stephen Law theory (we don't have a motive) or compliance by the Ken Ham theory (he owns a knife) are not.

I'm warming up to this theme now. It seems that you can list out alleged evidence on both sides and see whether it can be deduced from the theory and not by the other:

1. GenesisYou can deduce from "God made the world as described in a literal interpretation of Genesis" (and a few other assumptions) to the words of Genesis. You can also deduce from "The ancient Hebrews tried to explain the origins of the world" to the words of Genesis (Ratzinger does it very well in his "In the beginning"). Genesis is no evidence for Creationism.

2. You can DEDUCE the fossil record from evolution. It may be consistent with creaitonism, but you cannot DEDUCE it. The fossil record is evidence for evolution.

3. You can DEDUCE polystrate fossils from BOTH creationism and "godless evolutionist materialsit" science. No evidence either way.

Hi Kosh3 - to clarify a bit: I am not committed to the three conditions being necessary. I am not saying: fail all three, or even one or two, and the move is illegit. I am saying, pass all three, and the move is legit. And then I add that the creationists fail on two. Now that doesn't entail their move is illegit (because I don't say they are necessary conditions). But it does mean it cannot be legit for these kind of reasons.... so the onus is on them to explain why it is legit.

What's true is that the logic in this draft is not as clear as it should be, so this is very helpful!

Hi Tony. Deducibility is important - of course. But it is covered by my clear and precise predictions. Moreover, it's not enough for strong confirmation, as the astrology example shows. From astrology we can deduce that the predictions made by astrologers will be true. They are true! But that doesn't much confirm astrology.

The surprisingness of a theory's predictions is not same as the theory's having explanatory power, surely? e.g. The truth of astrology would *explain* the accuracy of the predictions, but the predictions don't strongly confirm the theory, because they are unsurprising.

Unless maybe explanatory power means - best available explanation? That might do it....

2. You can DEDUCE the fossil record from evolution. It may be consistent with creaitonism, but you cannot DEDUCE it. The fossil record is evidence for evolution.

You can't actually deduce the fossil record from evolution, only some aspects of it. From the theory of evolution you cannot deduce very many details of the fossil record at all - cf. quantum mechanics and chemistry! The fossil record is consistent with evolution, but then it is also, as you say, consistent with creationism.

Furthermore you are mistaking creationist science for something that (as mainstream science tends to) is trying to imitate modern physics - a little like mistaking continental philosophy for something aiming to emulate set theory (which is the foundation of modern mathematics, the queen of modern science). Creationist biology is trying to equal Darwinist biology on overall explanatory power (e.g. the existence of responsible agents, and their cultural heritage) - cf. the mainstream programme in mathematical science to found mathematics on set theory, which has been enormously successful: Even engineers may now learn Lebesque integration instead of Riemann integration. Set theory does not predict any better than informal maths does; indeed, all it can do is reproduce applicable maths, within a preferred metaphysical framework. Engineers may use infinitesimals to get their answers, but it is scientifically important that those infinitesimals can be reproduced within set theory. Physicists may use category theoretic entities, but again, foundational mathematicians will go to some lengths to show that category theoretic results can be reproduced within set theory.

Sorry for the length of that - but the analogies can be made arbitrarily good! I could go on and on with more scientific analogies (although I know more maths). The point is that creationist science can explain the fossil record. It matters not a jot that their explanations are often ad hoc and next to useless for applied scientific work: The same goes for most foundational work in mainstream science (much of which takes place within science departments).

Incidentally (boring I know) a better analogy would be with intuitionistic foundations for maths, since such deliberately aim to get slightly different results, rather than just reproducing standard informal maths; and even so, one or two professional mathematicians work on such foundations, and the formalistic mainstream counts them as mathematicians to the extent that they can end up with formal output - although such formality is not necessary, since another programme is to reproduce enough informal structure for modern science. Similarly, creationists who comply with scientific standards of publication can legitimately claim to be scientific (especially as the common sensicality of their work compares favourably with that of the mathematical constructivists (not to mention the particle physicists again) given those scarey statistics in your intro).

Yes, deductibility is covered by your definitions. (I do think deductibility is involved in vagueness. From “you will come into some money” we can only deduce “£1 or £2 or £3……”. It would be stretching it to say that “£3” was “deductible” from the prediction as only the disjunction of £3 and an infinite number of other amounts together is actually entailed by the prediction.)

I agree with “Best available explanation”, with the qualifier “best” removed. We have no option but to accept a proposition where it is the ONLY available explanation. If there are two or more rival explanations then we are free to pick and choose. There is a lack of an objective criterion for “best”.

As “only available explanation” is our desired end result, evidence for a theory would be evidence that leads towards it being the only explanation left. That would be evidence that can (1) be explained by the theory (2) but not by other theories.(1) is your first criterion(2) is, I think, the “sense” in which the prediction is surprising

The emphasis on deduction is to draw a clear distinction between “explanation” and “accommodation”. Things deductible from a creationist framework (polystrate fossils) are also deductible from an evolutionist framework. Things deductible from an evolutionist framework are, in general, not deductible from a creationist framework. We can readily create a scenario where the structure of human chromosome 2 ( http://youtube.com/watch?v=Gs1zeWWIm5M ) is deductible from evolutionary theory. We can construct, using the terms of the theory, a sequence of events were it would be inconsistent NOT to expect the chromosomes to look like that. We cannot construct a comparable deductive explanation in creation theory, we can accommodate it but nothing would make us EXPECT the chromosomes to look like that. So the prediction is surprising (“jaw-dropping” might be a better term).

Enigman, I think you can deduce “the fossil record” from evolutionary theory and a few auxiliary assumptions. You can’t deduce it in detail without huge numbers of auxiliary hypotheses. This is back to “detail” and “precision”. If theory-E predicts “a or b or c” then “a or b or c” is deductible from it. We can’t say that theory-E predicts “a”, or that it predicts “b”, just that it predicts “a or b or c”. Lets call “a or b or c” the single letter “d”. Theory-E predicts “d”. Now if Theory-C predicts “a or b or c or e or f or g” then it predicts “d or e or f or g”. As with theory-E we cannot say that theory-C predicts “d” or that it predicts “e” etc. We CAN however say that theory-E predicts “d”.

Evolutionary theory (with auxiliary assumptions) predicts a fossil record, maybe not in much detail but it predicts one: “d”. Creationist theory does not exclude it, but it predicts “a fossil record or something else”.

We have no option but to accept a proposition where it is the ONLY available explanation.

Still it would be wise to acquire other options, e.g. an appreciation of how much a mathematical model does not say, and of just how many models are actually available. Thinking of the Einsteinian revolution helps me with that.

But I suspect that most Darwinists bothering to oppose Creationists tend to picture the world much as Darwin did. (Science is applied common sense, for most scientists; mathematical models of their methodology are not so good as actual scientific theories.)

Consequently I also suspect that they are attacking straw-Creationists (constructed in part by their not especially stupid opponents). A creationist theory of biology can predict everything that evolutionary theory predicts, just by including the latter as an approximation to the more complex theory, any time it wants to (cf. most Newtonian applications being subsumed within a relativistic physics). What it can claim to have been doing recently is, working out some of the details of the approximation (cf. superstring theories). I've no idea if they intend to claim any such thing, but they can make such a move quite scientifically (and consistently with the Bible taken literally).

As for details, they may work both ways; e.g. fossils of early hominids are often cited, as evidence against Creationism, but can the evolution of man be explained by Darwinism? The fossil record is, as you say, compatible with Creationism; but furthermore, if we take ourselves seriously there is a mismatch between our knowledge of ourselves (as rational agents, as responsible subjects) and the biochemical mechanisms that are all that Darwinism predicts (insofar as it tries to predict more, it ends up in philosophical waters that make Creationism look tame). Just a thought.

My guess as to why Creationism is so popular is that the Darwinian story of the evolution of man is repellent to many of us. Suppose Darwinian theory is true. The question just becomes, why should such biochemical mechanisms as we would then be not just believe something more palatable - is there a Darwinian reason why not?

The Creationists give a reason to personally believe in Creationism (one that suits many voters' tastes) and can allow that some of our technologies use Darwinistic mathematical models (much as the Catholic church once allowed heliocentric modelling), so the Darwinian reason cannot be that the truth will be more likely to lead to physical success. That much the Creationists can have any time they want. After all, the Darwinians themselves say that understanding the mathematical model (and how it relates to empirical evidence) is the most important part of scientific practice; they themselves say that the materialistic metaphysics is entirely irrelevant scientifically.

So, people can accept that evolutionary theory is true, approximately (it is after all just a very good mathematical model, as Newtonian physics is), and that creationism is true, literally (or analogically, to taste), and have the best of both worlds (or at least avoid the worst of either).

Personally I think that this post of Stephen's is excellent (and I lean towards Ratzinger on this) but also that it may be worth asking yourselves where you want to get to. Do you want more believers in the common sense view of evolution? But then moves away from Darwin's world view (of ordinary objects in Newtonian spacetime), or towards a more accurate model of scientific methodology, will just introduce such dubious complexities as will actually put people off. (I don't really know of course, that's just my uninformed guess; I'm finding the more serious debate here very educational, thanks ;-)

I like this essay Stephen because it's simple and easy to follow. And I think this is the criteria for any argument. Your writing styles and accessibility, in this blog and your books, have inspired me (along with others) to start a philosophy degree later this year.

I don’t think Stephen could disagree with Ratzinger on the philosophy of science. As far as the philosophy of science goes you can’t fit a fag paper between the first few chapters of ‘In the beginning’ and Stephen Gould’s ‘Non-overlapping Magisteria’

“but also that it may be worth asking yourselves where you want to get to.”

It would take a book to completely “debunk” creationism. Even that may not succeed, as the creationists can change their theory to accommodate almost anything there is little opportunity for actually proving them wrong. So I think Stephen should concentrate, as he does, on “there is no evidence” for creationism. It predicts nothing that is not predicted by other means and fails to predict a lot of what is predicted by other means.

What I mean by ‘predict’ (and why I keep banging on about deduction) is that theory-E predicts ‘d’ if and only if ‘not-d’ contradicts theory-E. On the example above ‘not-d’ is incompatible with theory-E but compatible with theory-C. Theory-C predicts ‘d or e or f’. Call the former (entailment) “prediction” and the latter “accommodation”.

Now without theory-E I would expect ‘d or e or f’, with no other information I would have to assign equal probability to each outcome: 1/3. If theory-C predicted four different outcomes: 1/4, five then 1/5 etc. So the surprise factor is directly related to how much rival theories predict as opposed to accommodate the data.

In the criminal investigation example the blood on Stephen’s shirt would be surprising. It is accommodatible in many other scenarios but only “Stephen done it” would make you actually expect it, would make "no blood on Stephen's shirt" contradictory. The trouble with creationism is that there is no blood on anybody’s shirt, it just doesn’t predict anything that isn’t predicted by other theories. Evolution on the other hand is dripping with blood, has left its finger-prints all over the crime scene and has a very guilty expression.

BTW I think you’re absolutely right on the “repellent” nature of the Darwinian theory. Look at the “we didn’t evolve from apes, we evolved from a common ancestor!” screechings of people who do accept evolution. Even those who accept evolution are unwilling to face up to the fact that Great-Great-Great-Great….…..Grandad lived in trees and had a banana fixation.

o Second, there should be a sense in which the prediction is surprising and unexpected.

I might have put something more like

The predictions should be accurate and specific.

As with the example of the psychic, if a psychic told you that you would receive £123 on Tuesday the 29th of April at 3.01pmYou will meet a new colleague on April 30th at 11.58am who will have dark skin and be 6’2”.You will being to exhibit the symptoms of a cold on May 3rd. The cold will last for four days.

If all of these predictions came true exactly as predicted, most people would be given pause. None of them are particularly surprising, it is the accuracy of the predictions that lends weight to their believability.

Also, I have found that the main objection that creationists have with regard to the fossil record is the lack of transitional fossils. They claim that if evolution were true, we should see millions of fossils with partially developed limbs etc. A few words on this would close that particular door.

Good essay though, enjoyed it. Look forward to reading the final draft.

Your article is interesting and makes some good points, but it is missing the larger picture.

Not all Bible literalists believe in a six thousand year old earth. A literal understanding of Genesis allows a time period of unspecified length between verse 1 and verse 3. This could have been billions of years. In other words, in verse 1 God created the earth. The earth could have become filled with life. At some point, the surface of the earth became covered with water as described in verse 2. Then starting in verse 3, God restored the earth to a condition of having life on it. Those who believe in a 6,000 year old earth do not believe this because they literally believe the Bible. They believe it because they believe the religious traditions they grew up in. A literal reading of the Bible fully allows for an earth billions of years old even with life forms that existed for hundreds of millions of years.

You are correct in saying that more is required for evidence to confirm a theory than that the theory be consistant with the evidence.

So far, you have avoided the word "proof". Has science proved evolution has occurred? And if not, is it right to teach children in tax supported public schools in a country that prohibits government from hindering the free exercise of religion, that evolution is a fact if you are unable or unwilling to say you have proved that it happened?

You gave a definition of creationism that includes belief in a 6,000 year old earth, even tho not all creationists believe in a 6,000 year old earth. But that definition is convenient for you because the idea of a 6,000 year old earth is the easiest for you to try to refute. It is also the majority opinion among creationists who claim to believe the Bible literally, so that is no doubt another reason you define creationism that way.

I will also give a definition of evolution that I think expresses the majority thinking of evolutionists and the teaching of science in the public schools. Evolution is the teaching that life in all its variety arose on the earth only through natural causes. In other words, evolution as taught in the public schools does not allow for supernatural intervention by God in a process of new species descending from other species. If someone suggested that God intelligently and supernaturally made genetic changes over millions of years to produce new species descended from older ones, that is not "evolution".

To prove evolution is how life came to be, you have to prove that there was no supernatural intervention or creation in the origins of species. How can science do that if the scientific method does not allow for consideration of supernatural causes? You have to consider and examine the possibility of supernatural causes in order to rule them out. But science cannot even discuss the supernatural.

Many of those who believe in a literal reading of the Bible also see confirmation of the inspiration of the Bible in the predictive value of its prophecies, and these predictions and their fulfillment serve as evidence for the Bible just as scientific predictions about fossils suggest to scientists that more complex life forms appeared gradually on the earth.

Stephen, one of our readers suggested we encourage you to submit this entry for the next Carnival of the Elitist Bastards, taking place at Thoughts in a Haystackon October 25th. I believe your post would be an excellent fit! If you're interested, please email me at elitistbastardscarnival@gmail.com. Gracias!

Hi, I'm just dropping in from a post at Podblack (http://podblack.com/?p=1006) suggesting that I take a look at this essay.

I must say I'm very impressed (not to imply that I'm some sort of authority on the matter though). The essay was very well-written and covered a lot of great points against creationism. I especially liked your explanation of why fitting a theory to evidence is different to getting the evidence to support the theory.

Don't let comments by creationists on this post get you down: I've come to believe that they only really attack the good stuff!

This was very interesting, but as you said, could be taken much further. I've noticed, from reading creationist "scientific studies," that they spend a crazy amount of time trying to disprove scientific theories, such as evolution and the age of the earth, and yet don't bother to find evidence to support their own hypothesis. They consider their view the default, automatically correct if a hole were to be punished in the established theories. As we know though, that's not how science works. Science requires a testable hypothesis. The hypothesis about fossils, from an evolutionary standpoint, was then supported by the evidence. Creationism makes no such hypothesis. They usually come in only after evidence has been found so that they can create a story to try and match it, yet through our history any standing belief/hypothesis they had, such as the earth being flat, was later proven false. Now they make no real hypothesis, content to twist facts but not to search for any of their own.

The two papers I recall reading were both poorly done. The first started off by creating a date based on the "6th day of creation week," yet have no supporting evidence or source to establish evidence of this particular time. The second was going after rock dating techniques that haven't been used for 30 years.

As for the spy dog example, I don't think the argument you made holds water. It makes sense to the layman, perhaps, but the fact is no evidence was ever produced. Saying that the transmitters in the dogs' heads were made from a flesh-like material might be seen as a hypothesis, and may seem supported since we find only dog brain and no identifiable transmitter, the fact is science is much like the law in the sense that someone is considered innocent until proven guilty. It is up to the accuser to provide enough evidence to reach a guilty verdict. Saying there is a transmitter in dogs should be proven by those that claim such to show you a transmitter, not make an excuse as to why it can't be found. If I say there is an alien bomb under the ground in my yard, it is up to me to prove it by providing evidence, the bomb for example. A doctor shouldn't just say your symtoms match that of cancer, even though there are other diseases it also could be, you have to prove cancer.

I really enjoyed reading your article. I found this as an informative and interesting post, so i think it is very useful and knowledgeable. I would like to thank you for the effort you have made in writing this article.

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